title: Foveolar choroidal blood flow in age-related macular degeneration.
abstract: OBJECTIVE
  To compare measurements of the foveolar choroidal blood circulation in subjects with nonexudative, age-related macular degeneration (AMD) with those of control subjects.
  
  
  METHODS
  Laser Doppler flowmetry was used to assess relative choroidal blood velocity (ChBVel), volume (ChBVol), and flow (ChBFlow) in the center of the fovea. Measurements were obtained in 20 eyes of 20 subjects with 10 or more large drusen, visual acuity of 20/32 or better, and no evidence of choroidal neovascularization. Findings obtained in these subjects were compared with those of 10 eyes of 10 age- and blood pressure-matched control subjects with no large drusen. Foveolar choroidal blood flow measurements were obtained by asking the study participants to fixate on a probing laser beam.
  
  
  RESULTS
  No significant differences in average age, blood pressure, or intraocular pressure were observed between subjects with AMD and control subjects. In subjects with AMD, average ChBVol was 0.24 +/- 0.08 (+/- 1 SD) arbitrary units (AU); this value was 33% lower than that of control subjects (0.36 +/- 0.11 AU; two-tailed, independent Student's t-test, P = 0.005). Average ChBVel, conversely, was not significantly different from normal (0.44 +/- 0.07 AU) in subjects with AMD (0.44 +/- 0.10 AU). Average ChBFlow in subjects with AMD (8.7 +/- 3.1 AU) was 37% lower than that of control subjects (13.7 +/- 3.5 AU) (P = 0.0005). Average blood flow pulsatility was 6% higher in subjects with AMD (0.71 +/- 0.15) than in control subjects (0.66 +/- 0.14), but this difference was not statistically significant (P = 0.42).
  
  
  CONCLUSIONS
  Average ChBFlow in the nonexudative stages of AMD is lower than that of age-matched controls, and the effect is caused mainly by a decrease in ChBVol. Further studies are needed to elucidate whether decreased ChBFlow plays a role in the development of choroidal neovascularization, and whether ChBFlow measurements may help identify subjects with AMD at risk for developing choroidal neovascularization.
authors.affiliation: Department of Ophthalmology, Scheie Eye Institute, School of Medicine, University of Pennsylvania, Philadelphia 19104, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Grunwald
authors.forename: S M
authors.initials: SM
authors.lastname: Hariprasad
authors.forename: J
authors.initials: J
authors.lastname: DuPont
authors.forename: M G
authors.initials: MG
authors.lastname: Maguire
authors.forename: S L
authors.initials: SL
authors.lastname: Fine
authors.forename: A J
authors.initials: AJ
authors.lastname: Brucker
authors.forename: A M
authors.initials: AM
authors.lastname: Maguire
authors.forename: A C
authors.initials: AC
authors.lastname: Ho
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity; D001794:Blood Pressure; D002829:Choroid / Q000098:blood supply*; D005260:Female; D005584:Fovea Centralis / Q000098:blood supply*; D006801:Humans; D007429:Intraocular Pressure; D017078:Laser-Doppler Flowmetry; D008268:Macular Degeneration / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D014792:Visual Acuity